Navistar has revealed the results of the International SuperTruck II, a project in partnership with the U.S. Department of Energy (DOE). Navistar says that the International SuperTruck II has demonstrated a 16 miles per gallon (MPG) fuel efficiency through hybridization and a 170 percent improvement in freight efficiency over the 2009 International SuperTruck I.
Navistar took new technical approaches to weight reduction from rolling resistance technologies, aerodynamic improvements, and powertrain technologies to help reduce the dependency on fossil fuels in the commercial vehicle sector.
"With co-funding by the DOE, Navistar engineers experimented with prospective technologies not currently available in the Class 8 truck market to accelerate the impact of sustainable mobility," said Russ Zukouski, chief engineer of global innovation and principal investigator for the Supertruck programs. "The team concentrated its design on high-voltage electrification, utilizing hybrid technology on a path toward full electrification that has the potential to be commercialized in fully electric vehicles and improve customers' total cost of ownership (TCO) and business operations."
International SuperTruck II focused on vehicle efficiency improvements through hybridization and aerodynamics. Navistar says that this resulted in a demonstration of 170 percent improvement in vehicle freight efficiency, 55 percent engine brake thermal efficiency, assessed TCO opportunities for individual technologies, and high-voltage electrification efforts modelling hybrid technologies that can be utilized for fully electric vehicles.
"Navistar is the only OEM to build a trailer to provide the most accurate testing results possible," said Dean Oppermann, chief engineer, Advanced Truck. "It includes a 100 percent composite box designed for minimum aerodynamic drag with lightweight integrated cross members, controlled underbody flow with composite aero treatments, next-generation solar panels with connectivity options, and ride height control."
International SuperTruck II was built as a hybrid vehicle featuring a combustion engine with high-voltage accessories and technologies. The truck was developed in partnership with Bosch. Engine improvements were made in key areas including combustion, friction, gas exchange, and airflow through the engine. A redesigned cylinder head with a dual overhead cam engine and enhanced fuel system resulted in a two percent fuel economy improvement when compared to the International SuperTruck I. Aftertreatment system improvements included diesel exhausted fluid (DEF) dosing, improved mixing and lower restrictions, new selective catalytic reduction (SCR) formulations for high-NOx reduction, and reduced cold-start activation time.
"A full system approach was required to achieve 55.2 percent brake thermal efficiency," said Jim Cigler, chief engineer at Advanced Engine. "Opportunities were identified by internal engineering teams along with research partner Argonne National Laboratory through detailed analysis and simulation. System suppliers such as Bosch, Jacobs Vehicle Systems, and Applied Nano Systems (ANS) brought new approaches to key systems that enabled laboratory success and yielded real-world fuel economy improvements. Navistar was able to identify new ways to push our engines to the next level of efficiency."
International SuperTruck II highlighted connectivity with predictive cruise control, as well as leveraging technologies and information within the larger TRATON Group to explore vehicle-to-everything technologies.
"Our goal is to continue to advance internal combustion engine technology as efficiently and sustainably as possible until there is parity with zero-emissions vehicles," said Opperman. "Development of both technologies concurrently ensures a smooth transition of technology to best serve customer needs. We are focused on the entire product ecosystem – product development itself, as well as infrastructure charging, service and support of vehicle operation, end of life for batteries."
